This invention relates generally to the field of electronic devices and systems, and more specifically to electronic switching technology.
A relay or switch may be used to change an electrical signal from a first state to a second state. In general there may be more than two states. In applications that require a small switch geometry or a large number of switches within a small region, MEMS fabrication techniques may be used to create switches with a small footprint. A semiconductor switch may be used in a variety of applications, such as industrial equipment, telecommunications equipment and control of electro-mechanical devices such as ink jet printers.
In switching applications, the use of piezoelectric technology may be used to actuate a switch. Piezoelectric materials have several unique characteristics. A piezoelectric material can be made to expand or contract in response to an applied voltage. This is known as the indirect piezoelectric effect. The amount of expansion or contraction, the force generated by the expansion or contraction, and the amount of time between successive contractions are important material properties that influence the application of a piezoelectric material in a particular application. Piezoelectric material also exhibits a direct piezoelectric effect, in which an electric field is generated in response to an applied force. This electric field may be converted to a voltage if contacts are properly coupled to the piezoelectric material.
The indirect piezoelectric effect is useful in making or breaking a contact within a switching element, while the direct piezoelectric effect is useful in generating a switching signal in response to an applied force.
A method and structure for an electrical switch is disclosed. According to the structure of the present invention, a liquid-filled chamber is housed within a solid material. Switch contacts within the liquid-filled chamber are coupled to the solid material, while piezoelectric elements are coupled to a plurality of membranes. The plurality of membranes are coupled to the liquid-filled chamber. The plurality of switch contacts are coupled to a plurality of liquid metal globules. A slug is coupled to two of the plurality of switch contacts and one or more of the plurality of liquid metal globules. According to the method of the present invention, a piezoelectric element is actuated, causing a membrane element to be deflected. The deflection of the membrane element increases pressure of actuator liquid and the increase in pressure of the actuator liquid causes the slug to move from a first two switch contacts to a second two switch contacts. The pressure of the actuator fluid and the movement of the slug breaks a liquid metal connection between a first switch contact and a second switch contact of the electrical switch.